Method for curing medium-radioactivity alkaline slurry

Abstract

The invention discloses a method for solidifying medium-radioactivity alkaline slurry, and belongs to the technical field of radioactive waste treatment. The method specifically comprises the following steps: uniformly mixing the radioactive waste liquid and a water reducing agent, and completely dissolving to obtain dissolved waste liquid; uniformly mixing the Portland cement and the slag powder, sequentially adding the medium-radioactivity alkaline slurry and part of the dissolved waste liquid, and stirring; and adding the residual dissolved waste liquid in batches in a stirring state, stirring until the mixture is in a flowing cement-like mortar shape, filling into a mold, solidifying, and maintaining, thereby completing the solidification of the medium-radioactivity alkaline slurry, and obtaining a solidified body of the medium-radioactivity alkaline slurry. According to the invention, the medium-radioactivity-level alkaline slurry can be solidified to form a stable cement solidified body in a mode of minimizing capacity increase, so that long-term temporary storage or disposal of radioactive wastes is facilitated, and the current storage risk of the medium-radioactivity-level alkaline slurry is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of radioactive waste treatment, and in particular relates to a method for solidifying moderately radioactive alkaline mud. Background Art

[0003] This technology is a solidification formula for moderately radioactive alkaline mud, which can provide a treatment method for radioactive waste mud and eliminate the nuclear safety risks caused by storage as soon as possible. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] The patent of this invention aims to solve the problem of treating alkaline mud with medium radioactivity level formed in the nuclear industry process. By adopting this technology, the alkaline mud with medium radioactivity level can be solidified into a cement body, and its compressive strength and anti-leaching properties meet the requirements of GB14569.1-2021, thus solving the risk of long-term temporary storage of radioactive alkaline mud.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a method for solidifying moderately radioactive alkaline mud.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0009] The radioactive waste liquid and the water reducing agent are mixed and completely dissolved to obtain dissolved waste liquid;

[0010] After the silicate cement and slag powder are evenly mixed, the medium-radioactive alkaline mud and part of the dissolved waste liquid are added in sequence and stirred; under the stirring state, the remaining dissolved waste liquid is added in portions and stirred until the mixture becomes a flowing cement mortar-like state, molded, solidified and cured, thus completing the solidification of the medium-radioactive alkaline mud and obtaining a solidified body of the medium-radioactive alkaline mud.

[0011] The mass volume ratio of the silicate cement, slag powder, moderately radioactive alkaline mud and partially dissolved waste liquid is 420-500 g: 200-300 g: 170-238 mL: 100 mL.

[0012] As a preferred embodiment of the method for solidifying moderately radioactive alkaline mud of the present invention, the radioactive waste liquid has a pH value of ≤9, a rotational viscosity of 900 mPaS, a water content of 40-60%, and a density of 1.1-1.35 g / mL.

[0013] As a preferred embodiment of the method for solidifying moderately radioactive alkaline mud of the present invention, the water reducer includes one or more of lignin sulfonate water reducer, naphthalene-based high-efficiency water reducer, melamine-based high-efficiency water reducer, aminosulfonate-based high-efficiency water reducer, fatty acid-based high-efficiency water reducer and polycarboxylate-based high-efficiency water reducer.

[0014] As a preferred embodiment of the method for solidifying moderately radioactive alkaline sludge of the present invention, the mass volume ratio of the water reducing agent to the radioactive waste liquid is 1-3 g: 187-227 mL.

[0015] As a preferred embodiment of the method for solidifying moderately radioactive alkaline mud of the present invention, the silicate cement comprises one or more of 425, 525 or 625.

[0016] As a preferred embodiment of the method for solidifying moderately radioactive alkaline mud of the present invention, the slag powder includes one or more of S95 or S100.

[0017] As a preferred embodiment of the method for solidifying moderately radioactive alkaline mud of the present invention, the remaining dissolved waste liquid is added in batches of 15 to 20 mL each time until it is finished.

[0018] As a preferred embodiment of the method for solidifying moderately radioactive alkaline mud of the present invention, the fluidity of the cement mortar-like mixture is 115-140 mm.

[0019] As a preferred embodiment of the method for solidifying moderately radioactive alkaline mud of the present invention, the solidification time is 16 to 17 hours, and the curing time is 25 to 30 days.

[0020] As a preferred embodiment of the method for solidifying moderately radioactive alkaline mud of the present invention, the water content of the solidified body of the moderately radioactive alkaline mud is 40-60%, and the volume inclusion rate is 32-45%.

[0021] Beneficial effects of the present invention:

[0022] The present invention can solidify the alkaline mud with medium radioactivity level into a stable cement solidified body in a way of minimizing volume increase, which is convenient for long-term temporary storage or disposal of radioactive waste and greatly reduces the current storage risk of the alkaline mud with medium radioactivity level. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0024] Figure 1 The figure is a schematic flow chart of the method for solidifying moderately radioactive alkaline mud according to the present invention. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0026] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0027] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0028] The raw materials used in the present invention are all commercially available unless otherwise specified.

[0029] The performance of the material prepared in the embodiment of the present invention was tested as follows:

[0030] The compressive strength and anti-leaching properties of the cured body were measured with reference to GB14569.1-2021.

[0031] Example 1

[0032] This embodiment provides a method for solidifying moderately radioactive alkaline mud. Figure 1 , specifically:

[0033] 1. Put 207mL of radioactive waste liquid with pH ≤ 9 into a 500mL glass beaker, add 2g of polycarboxylate water reducer, and stir with a glass rod to dissolve it completely to form dissolved waste liquid;

[0034] 2. Add 500g of ordinary Portland cement (425) and 300g of slag powder (S95) into a stirring pot and mix well;

[0035] 3. Add 213 mL of moderately radioactive alkaline slurry to the stirring pot and immediately add 100 mL of dissolved waste liquid;

[0036] 4. Place the stirring pot on the mixer and stir at a low speed. Add 20 mL of the remaining dissolved liquid into the stirring pot and stir it into a flowing cement slurry. Take it out and measure its fluidity of 130 mm.

[0037] 5. Stop stirring, pour the prepared mixed waste mud mortar into a Φ50mm×50mm test mold to prepare a test mold, the final setting time is 16h, and then cure for 28 days to form a solidified body of medium-radioactive alkaline mud with a water content of 50%.

[0038] Example 2

[0039] The difference between this embodiment and embodiment 1 is that the volume of the radioactive waste liquid is adjusted to 227 mL, and the rest of the preparation process is the same as that of embodiment 1, and a solidified body of moderately radioactive alkaline mud is obtained.

[0040] Example 3

[0041] The difference between this embodiment and embodiment 1 is that the volume of the radioactive waste liquid is adjusted to 187 mL, and the rest of the preparation process is the same as that of embodiment 1, and a solidified body of moderately radioactive alkaline mud is obtained.

[0042] The performance of the solidified body obtained in the above embodiment was tested, and the comparison results with those in embodiment 1 are shown in Table 1.

[0043] Table 1

[0044] Example 1 Example 2 Example 3 Compressive strength(mPa) 12.5 9.82 9.57

[0045] It can be seen from the above table that adjusting the volume of radioactive waste liquid has a significant impact on the effect of the solidification method. This is because under the same conditions, when the amount of water required for solidification is at the minimum demand, the compressive strength of the solidified body formed is slightly higher. If the volume of radioactive waste liquid is increased, the fluidity of the cement slurry may be reduced, because the water in the waste liquid will increase the viscosity of the slurry, thereby affecting its fluidity and castability. This may lead to a decrease in the uniformity and density of the final solidified body, thereby affecting its mechanical properties and durability. In addition, too much waste liquid may also cause the internal pressure of the cement slurry to increase, resulting in cracks or cracks in the solidified body, affecting the solidification effect. According to the results in the above table, the volume of radioactive waste liquid in the present invention is 207mL to obtain the best technical effect.

[0046] Example 4

[0047] The difference between this embodiment and embodiment 1 is that the addition amount of the water reducing agent is adjusted to 1 g, and the rest of the preparation process is the same as that of embodiment 1, and a solidified body of moderately radioactive alkaline mud is obtained.

[0048] Example 5

[0049] The difference between this embodiment and embodiment 1 is that the addition amount of the water reducing agent is adjusted to 3 g, and the rest of the preparation process is the same as that of embodiment 1, and a solidified body of moderately radioactive alkaline mud is obtained.

[0050] The performance of the solidified body obtained in the above embodiment was tested, and the comparison results with those in embodiment 1 are shown in Table 2.

[0051] Table 2

[0052] Example 1 Example 4 Example 5 Compressive strength(mPa) 12.5 7.75 7.83

[0053] It can be seen from the above table that adjusting the polycarboxylic acid water-reducing agent has a significant impact on the effect of the curing method of the present invention. If the water-reducing agent is added in excess, the cement slurry may be too thin, the fluidity may be excessively increased, and it may be difficult to control the operability during the molding process. In addition, excessive water-reducing agent may affect the microstructure of the cement stone, increase the risk of bleeding and segregation, and reduce the compressive strength and durability of the solidified body. Reducing the amount of water-reducing agent added may reduce the fluidity of the cement slurry, making it difficult to stir the cement slurry evenly, affecting the uniformity of the cement slurry and the density of the solidified body. In addition, the reduction in fluidity may affect the pouring and molding of the cement slurry, resulting in an uneven internal structure of the solidified body. According to the results in the above table, the mass volume ratio of the water-reducing agent and the radioactive waste liquid in the present invention is 2g:207mL to obtain the best technical effect.

[0054] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for solidifying moderately radioactive alkaline mud, characterized in that: include, The radioactive waste liquid and the water reducing agent are mixed and completely dissolved to obtain dissolved waste liquid; After the silicate cement and slag powder are evenly mixed, the medium-radioactive alkaline mud and part of the dissolved waste liquid are added in sequence and stirred; under the stirring state, the remaining dissolved waste liquid is added in portions and stirred until the mixture becomes a flowing cement mortar-like state, molded, solidified and cured, thus completing the solidification of the medium-radioactive alkaline mud and obtaining a solidified body of the medium-radioactive alkaline mud. The mass volume ratio of the silicate cement, slag powder, moderately radioactive alkaline mud and partially dissolved waste liquid is 420-500 g: 200-300 g: 170-238 mL: 100 mL.

2. The method for solidifying moderately radioactive alkaline mud according to claim 1, characterized in that: The radioactive waste liquid has a pH value of ≤9, a rotational viscosity of 900 mPaS, a water content of 40-60%, and a density of 1.1-1.35 g / mL.

3. The method for solidifying moderately radioactive alkaline mud according to claim 1, characterized in that: The water reducer includes one or more of lignin sulfonate water reducer, naphthalene series high efficiency water reducer, melamine series high efficiency water reducer, amino sulfonate series high efficiency water reducer, fatty acid series high efficiency water reducer and polycarboxylate series high efficiency water reducer.

4. The method for solidifying moderately radioactive alkaline mud according to claim 2 or 3, characterized in that: The mass volume ratio of the water reducing agent to the radioactive waste liquid is 1-3 g: 187-227 mL.

5. The method for solidifying moderately radioactive alkaline mud according to claim 1, characterized in that: The silicate cement includes one or more of 425, 525 or 625.

6. The method for solidifying moderately radioactive alkaline mud according to claim 1, characterized in that: The slag powder includes one or more of S95 or S100.

7. The method for solidifying moderately radioactive alkaline mud according to claim 1, characterized in that: The remaining dissolved waste liquid is added in portions, with 15 to 20 mL added each time, until it is complete.

8. The method for solidifying moderately radioactive alkaline mud according to claim 1, characterized in that: The fluidity of the cement mortar-like mixture is 115 to 140 mm.

9. The method for solidifying moderately radioactive alkaline mud according to claim 1, characterized in that: The solidification time is 16 to 17 hours, and the curing time is 25 to 30 days.

10. The method for solidifying moderately radioactive alkaline mud according to claim 1, characterized in that: The water content of the solidified body of the medium-radioactive alkaline mud is 40-60%, and the volume content is 32-45%.

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